This invention relates to a thermal printer, and more particularly to a thermal printer having a character correcting function to erase characters or symbols recorded by thermal transfer printing.
Thermal printers have been developed wherein a thermal transfer medium having a thermally fusible material thereon is positioned between record paper and a thermal head, and a plurality of heat generating elements provided on the thermal head are heated to melt the thermally fusible material thereon in order to transfer it onto the record medium. Comparing with printers of other types, thermal printers of this type have an advantage that they do not make noises and can be produced at a low cost.
Recently, such thermal printers are being applied to electronic typewriters and the like. In such typewriters, a correcting function to erase recorded characters or symbols is essentially required. However, thermal printers normally have no effective correcting means for erasing characters or symbols which are once recorded by transfer onto record paper in order to correct them. Also developed these days are thermal printers of a different type wherein pigment of the same color with record paper is painted over characters or symbols recorded on the record paper to effect correction thereof, using an erasing ribbon provided independently of a thermal transfer medium in order to erase such characters or symbols. However, such correction requires an erase ribbon and a change-over mechanism for changing over between a thermal transfer medium and the erase ribbon, resulting in complication and increase of the size of the mechanism. Besides, there is a drawback that high quality recording is hindered by unevenness of a surface of pigment when rerecording on the pigment painted over the characters or symbols.